Internal combustion engines, such as four stroke engines, which generate power from the combustion of fuel are well known. The energy provided by such engines may be used in a wide range of applications such as motor vehicles.
Such engines are not completely efficient so that not all of the energy provided by the engines is used to provide useful work. It is beneficial to provide internal combustion engines which enable energy, which would otherwise be wasted, to be harnessed and used for any suitable purpose.